The purpose of this interdisciplinary project is to accumulate information on the relation between physical and psychological health of captive primates and their social housing conditions. This information is needed to successfully manage existing colonies of AIDS animal models, such as the chimpanzee (Pan troglodytes), rhesus macaque (Macaca mulatta), and pigtail macaque (M. nemestrina). Data collected on nonhuman primates under a variety of conditions will be supplemented with a unique data base accumulated during previous research. Standardized behavioral protocols and a computerized data base will enhance the ability of national breeding programs to justify existing housing conditions and/or provide an empirical basis for the design of future facilities. One of the envisaged end-products is a guide with behavioral data collection techniques, basal levels of easy-to-observe behavior patterns, as well as general health information. At the same time, the proposed research is part of an ongoing effort to develop a new theoretical model of environmental effects on aggressive behavior. The existing model, which attributes aggression levels to crowding, has serious flaws. Nonhuman primates have many checks and balances on aggression and violence, and appear to effectively cope and neutralize social tensions related to high population densities through appeasement and peacemaking. Research on chimpanzees will concern three main conditions: small groups in indoor/outdoor runs; larger groups in outdoor compounds; and, zoo groups in naturalistic enclosures. The chimpanzees will be observed with existing, detailed methods to determine the frequency of aggressive behavior, affiliation patterns, play, reproductive behavior, etc. The proposed study seeks to integrate behavioral and veterinary measures of well-being while paying special attention to measures of environmentally induced stress, ranging from behavioral stress measures to fecal cortisol levels, and immunological data. Research on pigtail macaques will be modeled after a previous large-scale study of rhesus monkeys. It will involve corral-housed groups as well as small harem groups. The study of pigtail macaques will be entirely observational and behavioral.